JP3073841B2 - Embossing method of plastic sheet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a CRT (Cathode Ray
The present invention relates to a method of embossing a plastic sheet used as a non-glare plate for a screen used in a VDT (Visual Display Terminal) or the like.

[0002]

2. Description of the Related Art As a non-glare plate which suppresses disturbing reflection of a screen of a display device such as a CRT due to sunlight or indoor lighting,
There is a demand for a plate having a highly uniform and fine embossed surface. This processing method includes a press roll,
There is a method in which the surface of the press plate is made uneven by etching, engraving, or the like in advance, and the plastic sheet is heated and pressed with this, or a polyester film subjected to sand blasting is stacked and heated and pressed to emboss the plastic sheet.

As another processing method, silica (SiO 2) having a particle size of about 0.1 to 1.0 μm is added to a binder resin.
₂ ) There is a method in which an ink in which an inorganic material such as calcium carbonate (CaCO ₃ ) is dispersed as a filler is screen-printed on a plastic sheet and embossed. Since the binder resin is required to have scratch resistance and stain prevention,
Hard coating resins such as those cured by UV irradiation or heating are particularly used.

[0004]

However, in the former processing method, the surface of the plastic sheet is 0.5 to 2 μm.
The limit is to form irregularities of about m, and the required 0.0
It is difficult to uniformly form an embossed pattern having irregularities of about 5 to 0.2 μm. In addition, each time the grade is changed, the press rolls and press plates must be redesigned, resulting in a large increase in cost.

In the latter method of screen printing,
Variation due to uneven dispersion of filler in ink,
Yield is about 50% due to clogging of screen, defects such as sagging, mixing of dust, etc. In addition, factors such as pot life of ink, dispersion processing, screen care, management of processing atmosphere, setting of drying conditions, etc. Therefore, further reduction in yield cannot be avoided.

[0006]

Means for Solving the Problems The present invention solves the above-mentioned problems, and a first invention is to provide a plastic sheet having a filler having a particle size of 0.1 to 1.0 μm on a plastic sheet.
A biaxially stretched polyester film (hereinafter simply referred to as an embossed film) having a thickness of 2 to 500 μm kneaded with 0.1 to 20 parts by weight with respect to 0 part by weight is superposed, and both are uniformly heated and pressed. The gist of the present invention is a method for embossing a plastic sheet, characterized in that the embossed film is peeled off and embossed finely and uniformly.

A second invention for performing more uniform embossing is to provide a plastic sheet having a particle size of 1.0%.
A biaxially stretched polyester film (hereinafter simply referred to as a clear film) having a thickness of 2 to 100 μm, in which a filler of μm or less is kneaded in an amount of 20 parts by weight or less based on 100 parts by weight of the resin, and an embossed film, The gist of the present invention is to provide a method of embossing a plastic sheet, which comprises uniformly heating and pressurizing the three members, peeling off the embossed film and the clear film, and performing fine and uniform embossing.

As a plastic sheet, polyolefin (PP), polyethylene (PS), acrylic (PMMA), polycarbonate (PC), polyvinyl chloride (PVC), crystalline polyethylene terephthalate (C-PETA), amorphous Polyethylene terephthalate (A-PET) or the like is used, and acrylic, polycarbonate, and polyvinyl chloride are suitable from the viewpoint of heat resistance, transparency, rigidity, and other physical properties.
m is preferable. To impart abrasion resistance to this plastic sheet, a urethane acrylate, a UV-curable hard coat of a polyester acrylate type, a hard coat of an acrylic type or a silicone type hard coat is applied to the surface layer, and the thickness of the hard coat layer is 2 to 20 μm. It is desirable to do.

As the embossed film, polyolefin, paper and the like can be considered. However, when embossing is performed, undulating irregularities are generated due to unevenness of the surface and unevenness of the material. However, it is preferable to use a biaxially stretched polyester film as in the present invention because embossing can be easily performed. The thickness of the embossed film is not particularly limited, but is particularly preferably 2 to 500 μm,
Those below m and above 500 μm are not used for general use.

The particle size of the filler is preferably from 0.1 to 1.0 μm. If it is less than 0.1 μm, the unevenness of the surface of the non-glare plate will be less than 0.05 μm.
More than 2 μm is inappropriate. The kneading amount of the filler in the embossed film is preferably 0.1 to 20 parts by weight with respect to 100 parts by weight of the resin, and if less than 0.1 part by weight, the density of irregularities on the surface of the non-glare plate per unit area decreases, The reflection of sunlight or indoor lighting cannot be suppressed, and if it exceeds 20 parts by weight, the density increases and the light transmittance deteriorates.

The thickness of the clear film is 2 to 100 μm
It is preferable that the thickness is less than 2 μm because there is no general use.
If it exceeds μm, the degree of reducing the unevenness of the surface of the non-glare plate becomes large, and it becomes impossible to suppress the reflection of sunlight or indoor lighting. The filler particle size and kneading amount are the same as in the embossed film.

In a general printing method, as shown in FIG. 2A, the unevenness is leveled in a convex shape, but in the first invention, as shown in FIG. 2B, the unevenness is formed in a concave shape. I have.
Further, by interposing a clear film, the shape of the concave edge is made into an arc shape as shown in FIG. 2C to improve the scratch resistance.

As shown in FIG. 1 (a), the heating and pressurizing methods include a plastic sheet A having a hard-coated surface, a clear film C obtained by kneading a small amount of filler into a biaxially oriented polyester film, and a filler. After the embossed film B kneaded into a biaxially stretched polyester film is sequentially stacked and passed through the heating and pressing roll 1, B,
C is peeled off. Thereby, the irregularities of the embossed film B and the clear film C are transferred to the plastic sheet A and embossed. Alternatively, as shown in FIG. 1 (b), there is a method in which three sheets A, B, and C are batch-pressed by a heating and pressing press 2.

[0014]

[Example] Heating temperature 150 ° C, pressurizing pressure 20kg / cm
^2. Table 2 shows the results of processing by combining various plastic sheets A, embossed films B, and clear films C as shown in Table 1 at a passage speed of 5 m / min.

[0015]

[Table 1]

[0016]

[Table 2]

Gloss: relative value (%) of luminance between the front and the 60 ° direction;
Haze: Diffuse transmittance / total light transmittance (%), (2.1
The following are non-standard *) Scratch resistance: 10 weights of 100% on steel wool
The degree of scratching when rubbing twice. 〇: scarcely damaged △: slightly damaged ×: damaged Overall evaluation: ◎: good 〇: slightly good ×: poor.

According to the processing method of the present invention, Examples 1 to 4
As shown in the figure, a good embossed plastic sheet was obtained, but according to the conventional method, Comparative Examples 1 to 7 were obtained.
As shown in Table 2, only non-standard plastic sheets were obtained.

[0019]

According to the processing method of the present invention, it is easy to manage a fine embossed pattern of a non-glare plate for a display device and to cope with various kinds of grades, and furthermore, a simple embossing line is used, It is extremely significant that it can be processed continuously and contributes to rationalization.

[Brief description of the drawings]

FIGS. 1A and 1B are explanatory views illustrating a processing method of the present invention.

FIG. 2A is a cross-sectional view of a concavo-convex portion on a conventional non-glare plate surface, and FIGS. 2B and 2C are cross-sectional views of a concavo-convex portion on a non-glare plate surface according to the present invention.

[Explanation of symbols]

 A: plastic sheet B: embossed film C: clear film 1: heating / pressing roll 2: heating / pressing

Claims (2)

(57) [Claims] 1. A plastic sheet having a particle size of 0.1
0.1 to 20 parts by weight of a filler having a thickness of 2 to 500 μm.
A method of embossing a plastic sheet, comprising: stacking the biaxially stretched polyester films of the above, heating and pressing both uniformly, and then peeling the biaxially stretched polyester film to perform fine and uniform embossing. 2. A plastic sheet having a particle size of 1.0
A biaxially stretched polyester film having a thickness of 2 to 100 μm and a filler having a particle size of 0.1 to 1.0 μm, and a filler having a particle size of 0.1 to 1.0 μm, The biaxially stretched polyester film having a thickness of 2 to 500 μm kneaded in an amount of 0.1 to 20 parts by weight with respect to the weight part is laminated in order, and the three members are uniformly heated and pressurized. A method for embossing a plastic sheet, wherein the film is peeled and embossed finely and uniformly.